1. Field of the Invention
The present invention relates to an optical communication system for transmitting optical signals including a plurality of wavelengths, an optical multiplexer/demultiplexer used in such optical communication system or the like, and a method of manufacturing the optical multiplexer/demultiplexer.
2. Related Background of the Invention
In an optical communication system, which transmits optical signals including a plurality of wavelengths, an optical multiplexer/demultiplexer for multiplexing or demultiplexing these optical signals including the plurality of wavelengths is used. Particularly, in an optical communication system (FTTH: fiber to the home) between end office and subscriber's home, the optical multiplexer/demultiplexer is required to be small in size and moderate in price. In an optical multiplexer/demultiplexer disclose in M. Yanagisawa, et al., “Low-loss and compact TFF-embedded silica-waveguide WDM filter for video distribution services in FTTH systems” OFC 2004, TuI 4, for example, two optical waveguides are formed so as to cross with each other on a member, a V-groove is formed so as to go through the cross section thereof and an optical filter is inserted in the V-groove and fixed therein with an adhesive agent. In the optical multiplexer/demultiplexer, among light components guided through one optical waveguide and reached to the V-groove, a light component of a certain wavelength is transmitted by the optical filter and is further guided through the one optical waveguide; and a light component of other wavelength is reflected by the optical filter, and guided through the other optical waveguide.